WWW Prefix - A definition

The WWW Prefix refers to settings in the Windows registry,
which specify
how domain names beginning with 'www' are prefixed. By default,
the 'www' prefix is set to 'http://' and if your computer has the default
settings you can see that domain names entered in the Internet Explorer address
field beginning
with 'www' are prefixed with 'http://'. For example, if you
enter 'www.kephyr.com' in your Internet Explorer browser it will be
replaced with the 'http://www.kephyr.com/' URL.

This setting in the registry can be used for both good and bad and many browser hijackers
employ this to redirect web traffic through their web site where they can open pop-up
windows or show other types of advertisements and then redirect you to the site you were going to in the first place.
For example, CoolWebSearch.ehttp
utilize this technique to prefix 'http://ehttp.cc/?' to domain names beginning with 'www' and 'www.'. When you
enter www.kephyr.com in your browser, you end up at 'http://ehttp.cc/?www.kephyr.com' for a fraction
of a second and then they redirect you to 'http://www.kephyr.com/'.

The WWW prefix is located in the registry under
'HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows \ CurrentVersion \ URL \ Prefixes \'
where also other prefixes can be specified. On a Windows XP Home machine with default
settings there are prefixes
for domain names beginning with the following: ftp, gopher, home, mosaic and www.

Reset the WWW prefix manually

To reset the WWW prefix settings, follow the instructions
below, which includes minor modifications to the registry.

Start the registry editor. This is done by clicking Start then Run.
(The Run dialog will appear.) Type regedit and click OK. (The registry editor will open.)

Browse to the key:
'HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows \ CurrentVersion \ URL \ Prefixes \'.
If this registry key does not exist, the web browser will use the
Default Prefix.

In the right pane, right-click the 'www' value and modify its data to 'http://'

In the right pane, delete the value called 'www.', if it exists.

Exit the registry editor.

Close all Internet Explorer browsers.

Your browser should now have the default WWW prefix, and you can verify this by
entering www.kephyr.com in the Internet Explorer address field.
The domain name should be replaced with the http://www.kephyr.com/ URL.